Water
You must have water if you intend to build. Your water may come from a public water supply, a mutual water company, well, stream, spring or other source, but you must have it. You must also be sure that you will have enough water and it will be of sufficient quality to provide for your needs. There are a number of reports of well levels dropping in certain areas, be careful.

Sonoma County has four groundwater availability zones. In the Northwest and some of the Western portion of the county groundwater availability is a real concern. In water scarce regions the County is now requiring that a well produce a minimum of 1 gallon per minute over a 12 hour period before a building permit will be issued.

How much water is enough? It depends on what you plan to do with your property; a hobby vineyard or large garden will add considerably to your needs. Always overestimate what you will require. You might determine that you will need a well that can produce a minimum of 3 gallons per minute. That would give you 180 gallons per hour and 4,320 gallons per day. Of course you will need a holding tank of sufficient size to provide water storage and for use in case of fire. In all new construction a water holding tank is required regardless of your well's production.

The quality of your water and the permanency of your water source is another issue to consider. Not all water is drinkable and water sources can dry up. I recommend that a buyer have the well tested for both quality and for production.Water quality and availability will be an area of concern for the foreseeable future in Sonoma County. Do your homework before you buy.